The present invention relates generally to underwater testing of targets, such as the hull of a ship, in regard to damage caused by shock waves produced by explosive detonation.
At the present time, shock testing of ship hulls by the U.S. Navy is conducted by detonation of relatively large underwater explosive charges at a substantial distance from the ship. In order to insure safety and minimize detrimental environmental effects resulting from such testing, expensive measures are taken that substantially increase the costs of such testing, involving time consuming assembly of costly parts. It is therefore an important object of the present invention to provide such shock wave testing involving detonation of an explosive charge underwater, that is substantially less costly and more quickly and easily performed.
In accordance with present invention, shock wave testing is performed by positioning a substantially small explosive charge relatively close to an underwater target and within an underwater shell enclosure having an open end from which focused shock waves emerge in a direction onto the target. The enclosure shell is conical shaped having a rigid inner liner externally covered by foam so as to focus shock waves produced by detonation onto the target such as a ship hull from the close location at sea or within a harbor, and by use of small quantities of explosive charge.